diff --git a/demos/gtk-demo/Makefile.am b/demos/gtk-demo/Makefile.am
index 088c2510ed..21efdd0f4c 100644
--- a/demos/gtk-demo/Makefile.am
+++ b/demos/gtk-demo/Makefile.am
@@ -158,7 +158,7 @@ dist_appsicon32_DATA = data/32x32/gtk3-demo.png data/32x32/gtk3-demo-symbolic.sy
 dist_appsicon48_DATA = data/48x48/gtk3-demo.png data/48x48/gtk3-demo-symbolic.symbolic.png
 dist_appsicon256_DATA = data/256x256/gtk3-demo.png data/256x256/gtk3-demo-symbolic.symbolic.png
 
-update_icon_cache = $(top_builddir)/gtk/gtk-update-icon-cache --ignore-theme-index --force
+update_icon_cache = $(top_builddir)/gtk/gtk-update-icon-cache$(EXEEXT) --ignore-theme-index --force
 
 install-data-hook: install-update-icon-cache
 uninstall-hook: uninstall-update-icon-cache
diff --git a/demos/widget-factory/Makefile.am b/demos/widget-factory/Makefile.am
index b9c481da6e..a97b9eac43 100644
--- a/demos/widget-factory/Makefile.am
+++ b/demos/widget-factory/Makefile.am
@@ -47,7 +47,7 @@ dist_appsicon32_DATA = data/32x32/gtk3-widget-factory.png data/32x32/gtk3-widget
 dist_appsicon48_DATA = data/48x48/gtk3-widget-factory.png data/48x48/gtk3-widget-factory-symbolic.symbolic.png
 dist_appsicon256_DATA = data/256x256/gtk3-widget-factory.png data/256x256/gtk3-widget-factory-symbolic.symbolic.png
 
-update_icon_cache = $(top_builddir)/gtk/gtk-update-icon-cache --ignore-theme-index --force
+update_icon_cache = $(top_builddir)/gtk/gtk-update-icon-cache$(EXEEXT) --ignore-theme-index --force
 
 install-data-hook: install-update-icon-cache
 uninstall-hook: uninstall-update-icon-cache